Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, United States.
Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, United States.
Bioorg Med Chem. 2021 Jan 1;29:115894. doi: 10.1016/j.bmc.2020.115894. Epub 2020 Nov 28.
MicroRNAs (miRNAs) are short noncoding RNAs that play a fundamental role in gene regulation. Deregulation of miRNA expression has a strong correlation with disease and antisense oligonucleotides that bind and inhibit miRNAs associated with disease have therapeutic potential. Current research on the chemical modification of anti-miRNA oligonucleotides (anti-miRs) is focused on alterations of the phosphodiester-ribose backbone to improve nuclease resistance and binding affinity to miRNA strands. Here we describe a structure-guided approach for modification of the 3'-end of anti-miRs by screening for modifications compatible with a nucleotide-binding pocket present on human Argonaute2 (hAgo2). We computationally screened a library of 190 triazole-modified nucleoside analogs for complementarity to the t1A-binding pocket of hAgo2. Seventeen top scoring triazoles were then incorporated into the 3' end of anti-miR21 and potency was evaluated for each in a cell-based assay for anti-miR activity. Four triazole-modified anti-miRs showed higher potency than anti-miR21 bearing a 3' adenosine. In particular, a triazole-modified nucleoside bearing an ester substituent imparted a nine-fold and five-fold increase in activity for both anti-miR21 and anti-miR122 at 300 and 5 nM, respectively. The ester group was shown to be critical as a similar carboxylic acid and amide were inactive. Furthermore, anti-miR 3' end modification with triazole-modified nucleoside analogs improved resistance to snake venom phosphodiesterase, a 3'-exonuclease. Thus, the modifications described here are good candidates for improvement of anti-miR activity.
MicroRNAs (miRNAs) 是短链非编码 RNA，在基因调控中发挥着重要作用。miRNA 表达失调与疾病密切相关，与疾病相关的 miRNA 结合并抑制 miRNA 的反义寡核苷酸具有治疗潜力。目前，抗 miRNA 寡核苷酸（anti-miRs）的化学修饰研究集中在磷酸二酯-核糖骨架的改变上，以提高核酸酶抗性和与 miRNA 链的结合亲和力。在这里，我们描述了一种通过筛选与存在于人 Argonaute2（hAgo2）上的核苷酸结合口袋相容的修饰来修饰 anti-miRs 3'端的结构导向方法。我们通过计算筛选了一个包含 190 个三唑修饰核苷类似物的文库，以与 hAgo2 的 t1A 结合口袋互补。然后将 17 个得分最高的三唑并入 anti-miR21 的 3'端，并在基于细胞的抗 miR 活性测定中评估每种化合物的效力。四种三唑修饰的 anti-miRs 比带有 3'腺嘌呤的 anti-miR21 具有更高的效力。特别是，带有酯取代基的三唑修饰核苷赋予了 anti-miR21 和 anti-miR122 在 300 和 5 nM 时的活性分别提高了九倍和五倍。酯基是关键的，因为类似的羧酸和酰胺是无活性的。此外，三唑修饰的核苷类似物对蛇毒磷酸二酯酶（一种 3'-外切核酸酶）的修饰改善了 anti-miR 的抗性。因此，这里描述的修饰是提高 anti-miR 活性的良好候选物。
